[New method to measure the weight of black holes]
A disk of hot gas and dust surrounds a black hole that is actively swallowing food. Astronomers have discovered that monitoring the changes in these scintillations can find out something that was difficult for us to measure in the past, that is, the weight of the black hole.
Astronomer Colin Burke of the University of Illinois at Urbana-Champaign said: “This is a new way to measure the weight of a black hole.” In addition, the researchers reported in the August 13th issue of “Science” that the The method can be used for any astrophysical object with an accretion disk, and it may even help to find elusive medium-sized black holes.
It is not easy to measure the mass of a black hole. First of all, we all know that it is actually difficult to see a black hole, but sometimes a black hole exposes itself when eating, that is, when gas and dust fall into the black hole, the matter will form a disk shape. At this time, the disc shape will be heated to a certain temperature, and then it will be brighter than the sum of all the stars in the galaxy.
[Only the Event Horizon Telescope (ETH) has measured black holes]
Measuring the diameter of a black hole with Einstein’s general relativity can estimate the mass, but only the Event Horizon Telescope (ETH) has done such a measurement, and so far only one black hole has been successfully measured. Other black holes are It is measured by observing their influence on the surrounding matter, but this requires a lot of data and is not applicable to every supermassive black hole.
In order to find other methods, Burke and his colleagues turned their attention to the accretion disk of black holes. Astronomers are not sure how the disk of the black hole flashes, but it seems that within a certain time span, the combination of small changes in light will cause Make the entire disc lighten or darken as a whole. Previous studies have suggested that the time when the disc fades, brightens, and fades again is related to the mass of the black hole in the center. But Burke believes these claims are controversial, and it doesn’t. Covers the full range of black hole masses.
[It may take years of observation to calculate the mass]
Then Burke and his colleagues collected 67 observations of black holes with known masses. The size of these behemoths ranged from 10,000 to 10 billion times the mass of the sun. From the perspective of the smallest black hole, the blinking time ranges from a few hours to Weeks, while the super-large black holes between 100 million and 10 billion times the mass of the sun blink more slowly, about every few hundred days.
Burke said: “In the future, the relationship between disk scintillation and black hole mass can tell astronomers a lot of information. This method provides a simpler method of measuring black holes than any previous technology, but it is not necessarily the fastest. To find a larger black hole, it would take hundreds of days, or even years of observation, to calculate their mass.”
Image source: MARK A. GARLICK SIMONS FOUNDATION
資料來源:Lisa Grossman(2021AUG 12).Measuring a black hole’s mass isn’t easy. A new technique could change that. Sciencenews
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